The yarn I'm working with is Elsabeth Lavold's Silky Wool, which is why I asked the question. I just blocked a couple of swatches and found out that twisted purls every other row defines and compresses the ribbing very nicely. K2p1 didn't look right. I didn't want to also twist the neck stitches because there are four ribs running up the front of the sweater I am going to knit, and I don't need to twist the stitches there.
A new knitting lesson learned.
Ceil (Ravelry: ceilr) Time is never a factor when joy is involved.